scholarly journals Surface Forces between Nanomagnetite and Silica in Aqueous Ca2+ Solutions Studied with AFM Colloidal Probe Method

2020 ◽  
Vol 4 (3) ◽  
pp. 41
Author(s):  
Illia Dobryden ◽  
Elizaveta Mensi ◽  
Allan Holmgren ◽  
Nils Almqvist
Keyword(s):  
Iron Ore ◽  
Adhesion Force ◽  
Surface Forces ◽  
Adhesion Forces ◽  
Interaction Forces ◽  
Colloidal Probe ◽  
Force Microscopy ◽  
Atomic Force ◽  
Repulsive Forces ◽  
Qualitative Changes

Dispersion and aggregation of nanomagnetite (Fe3O4) and silica (SiO2) particles are of high importance in various applications, such as biomedicine, nanoelectronics, drug delivery, flotation, and pelletization of iron ore. In directly probing nanomagnetite–silica interaction, atomic force microscopy (AFM) using the colloidal probe technique has proven to be a suitable tool. In this work, the interaction between nanomagnetite and silica particles was measured with AFM in aqueous Ca2+ solution at different pH levels. This study showed that the qualitative changes of the interaction forces with pH and Ca2+ concentrations were consistent with the results from zeta-potential measurements. The repulsion between nanomagnetite and silica was observed at alkaline pH and 1 mM Ca2+ concentration, but no repulsive forces were observed at 3 mM Ca2+ concentration. The interaction forces on approach were due to van der Waals and electrical double-layer forces. The good fitting of experimental data to the DLVO model and simulations supported this conclusion. However, contributions from non-DLVO forces should also be considered. It was shown that an increase of Ca2+ concentration from 1 to 3.3 mM led to a less pronounced decrease of adhesion force with increasing pH. A comparison of measured and calculated adhesion forces with a few contact mechanics models demonstrated an important impact of nanomagnetite layer nanoroughness.

Capillary Forces Studied with Atomic Force Microscopy

2007 ◽  
Vol 1025 ◽  
Author(s):  
Sahar Maghsoudy-Louyeh ◽  
Bernhard R. Tittmann
Keyword(s):  
Atomic Force Microscopy ◽  
Adhesion Force ◽  
Theoretical Calculations ◽  
Capillary Forces ◽  
Adhesion Forces ◽  
Coating Materials ◽  
Force Microscopy ◽  
Atomic Force ◽  
Repulsive Forces ◽  
Hydrophilic Materials

AbstractThe deposition of films and coatings is sometimes influenced by the presence of small amounts of moisture, which can affect the nucleation and growth processes. It is important to understand the behavior of coating materials–especially in semiconductors–in terms of hydrophilicity/hydrophobicity along with adhesion forces. Our technical approach centers on the use of the atomic force microscope (AFM) which was found to be a reliable tool for studying the surface characteristics of materials. In addition to obtaining topographic information, the AFM can also probe attractive or repulsive forces between the tip and the sample surfaces. In this research, a systematic study of the influence of humidity on the adhesion forces between different AFM tips (silicon and silicon nitride) and both hydrophilic and hydrophobic materials (quartz, calcite, mica, graphite) has been conducted using atomic force microscopy. Several force-distance curves measured by the M5 AFM have been gathered at a series of different humidity levels and different locations on the samples. In this paper, measurements of the adhesion force for hydrophobic and hydrophilic materials versus humidity are presented. The results show that the adhesion force on graphite which has hydrophobic character is independent of humidity variation. Results also show that the adhesion force for fused quartz, mica, and calcite which are hydrophilic materials, change dramatically with increasing humidity due to capillary forces. This is in good agreement with theoretical calculations.

scholarly journals Adhesion force mapping on wood by atomic force microscopy: influence of surface roughness and tip geometry

2016 ◽  
Vol 3 (10) ◽  
pp. 160248 ◽  
Author(s):  
X. Jin ◽  
B. Kasal
Keyword(s):  
Surface Roughness ◽  
Atomic Force Microscopy ◽  
Wood Surface ◽  
Adhesion Force ◽  
Data Interpretation ◽  
Natural Fibre ◽  
Force Distribution ◽  
Adhesion Forces ◽  
Force Microscopy ◽  
Atomic Force

This study attempts to address the interpretation of atomic force microscopy (AFM) adhesion force measurements conducted on the heterogeneous rough surface of wood and natural fibre materials. The influences of wood surface roughness, tip geometry and wear on the adhesion force distribution are examined by cyclic measurements conducted on wood surface under dry inert conditions. It was found that both the variation of tip and surface roughness of wood can widen the distribution of adhesion forces, which are essential for data interpretation. When a common Si AFM tip with nanometre size is used, the influence of tip wear can be significant. Therefore, control experiments should take the sequence of measurements into consideration, e.g. repeated experiments with used tip. In comparison, colloidal tips provide highly reproducible results. Similar average values but different distributions are shown for the adhesion measured on two major components of wood surface (cell wall and lumen). Evidence supports the hypothesis that the difference of the adhesion force distribution on these two locations was mainly induced by their surface roughness.

scholarly journals Measurement of Interaction Forces between Montmorillonite Particles in NaCl Solutions using a Colloidal Probe Atomic Force Microscopy

2006 ◽  
Vol 5 (3) ◽  
pp. 251-256
Author(s):  
Susumu KUROSAWA ◽  
Masashi MIZUKAMI ◽  
Hisao SATO ◽  
Jun NOZAWA ◽  
Keiichi TSUJIMOTO ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Interaction Forces ◽  
Colloidal Probe ◽  
Force Microscopy ◽  
Atomic Force

scholarly journals Nanoscale mapping of dielectric properties based on surface adhesion force measurements

2018 ◽  
Vol 9 ◽  
pp. 900-906 ◽  
Author(s):  
Ying Wang ◽  
Yue Shen ◽  
Xingya Wang ◽  
Zhiwei Shen ◽  
Bin Li ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Dielectric Properties ◽  
Adhesion Force ◽  
Model Systems ◽  
Adhesion Forces ◽  
Surface Adhesion ◽  
Storage Devices ◽  
Force Microscopy ◽  
Atomic Force

The detection of local dielectric properties is of great importance in a wide variety of scientific studies and applications. Here, we report a novel method for the characterization of local dielectric distributions based on surface adhesion mapping by atomic force microscopy (AFM). The two-dimensional (2D) materials graphene oxide (GO), and partially reduced graphene oxide (RGO), which have similar thicknesses but large differences in their dielectric properties, were studied as model systems. Through direct imaging of the samples with a biased AFM tip in PeakForce Quantitative Nano-Mechanics (PF-QNM) mode, the local dielectric properties of GO and RGO were revealed by mapping their surface adhesion forces. Thus, GO and RGO could be conveniently differentiated. This method provides a simple and general approach for the fast characterization of the local dielectric properties of graphene-based materials and will further facilitate their applications in energy generation and storage devices.

scholarly journals Comparative Analysis of Attachment to Chalcopyrite of Three Mesophilic Iron and/or Sulfur-Oxidizing Acidophiles

Minerals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 406 ◽  
Author(s):  
Qian Li ◽  
Baojun Yang ◽  
Jianyu Zhu ◽  
Hao Jiang ◽  
Jiaokun Li ◽  
...  
Keyword(s):  
Adhesion Force ◽  
Bacterial Attachment ◽  
Copper Recovery ◽  
Metal Sulfides ◽  
Acidithiobacillus Thiooxidans ◽  
Adhesion Forces ◽  
Force Microscopy ◽  
Atomic Force ◽  
Initial Adhesion ◽  
Sulfur Oxidizing

Adhesion plays an important role in bacterial dissolution of metal sulfides, since the attached cells initiate the dissolution. In addition, biofilms, forming after bacterial attachment, enhance the dissolution. In this study, interactions between initial adhesion force, attachment behavior and copper recovery were comparatively analyzed for Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans, and Leptospirillum ferrooxidans during bioleaching of chalcopyrite. The adhesion forces between bacteria and minerals were measured by atomic force microscopy (AFM). L. ferrooxidans had the largest adhesion force and attached best to chalcopyrite, while A. ferrooxidans exhibited the highest bioleaching of chalcopyrite. The results suggest that the biofilm formation, rather than the initial adhesion, is positively correlated with bioleaching efficiency.

scholarly journals Nanoporous Structure of Bone Matrix at Osteoporosis from Data of Atomic Force Microscopy and IR Spectroscopy

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
A. A. Gaidash ◽  
L. N. Sinitsa ◽  
O. A. Babenko ◽  
A. A. Lugovskoy
Keyword(s):  
Water Clusters ◽  
Bone Matrix ◽  
Bulk Water ◽  
Nanoporous Structure ◽  
Osteoporotic Bone ◽  
Adhesion Forces ◽  
Mineral Phase ◽  
Interaction Forces ◽  
Force Microscopy ◽  
Atomic Force

It was found that in an osteoporotic bone the fraction of nanosized pores decreases, the mineral phase amorphizes, hydrated shells around mineralized particles of the bone matrix thicken, and adhesion forces increase. This contributes to the formation of water clusters similar to bulk water clusters compared to the healthy bone tissue and leads to the accumulation of more viscous liquid with increased intermolecular interaction forces in the pores of the bone matrix. Given this, the rates of chemical reactions proceeding in the water phase of ultrathin channels of general parts of collagen fibrils decrease. Ultimately, nanopores of collagen-apatite interfaces lose, to a certain extent, the capability of catalyzing the hydroxyapatite crystallization.

scholarly journals Direct Measurement of Adhesion Force of Individual Aerosol Particles by Atomic Force Microscopy

Atmosphere ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 489
Author(s):  
Kohei Ono ◽  
Yuki Mizushima ◽  
Masaki Furuya ◽  
Ryota Kunihisa ◽  
Nozomu Tsuchiya ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Adhesion Force ◽  
Aerosol Particles ◽  
Sea Salt ◽  
Dust Particles ◽  
Adhesion Forces ◽  
Distance Curve ◽  
Ambient Particles ◽  
Force Microscopy ◽  
Atomic Force

A new method, namely, force–distance curve mapping, was developed to directly measure the adhesion force of individual aerosol particles by atomic force microscopy. The proposed method collects adhesion force from multiple points on a single particle. It also takes into account the spatial distribution of the adhesion force affected by topography (e.g., the variation in the tip angle relative to the surface, as well as the force imposed upon contact), thereby enabling the direct and quantitative measurement of the adhesion force representing each particle. The topographic effect was first evaluated by measuring Polystyrene latex (PSL) standard particles, and the optimized method was then applied on atmospherically relevant model dust particles (quartz, ATD, and CJ-1) and inorganic particles (ammonium sulfate and artificial sea salt) to inter-compare the adhesion forces among different aerosol types. The method was further applied on the actual ambient aerosol particles collected on the western coast of Japan, when the region was under the influence of Asian dust plume. The ambient particles were classified into sea salt (SS), silicate dust, and Ca-rich dust particles based on individual particle analysis (micro-Raman or Scanning Electron Microscope/Energy Dispersive X-ray Spectroscopy (SEM-EDX)). Comparable adhesion forces were obtained from the model and ambient particles for both SS and silicate dust. Although dust particles tended to show smaller adhesion forces, the adhesion force of Ca-rich dust particles was larger than the majority of silicate dust particles and was comparable with the inorganic salt particles. These results highlight that the original chemical composition, as well as the aging process in the atmosphere, can create significant variation in the adhesion force among individual particles. This study demonstrates that force–distance curve mapping can be used as a new tool to quantitatively characterize the physical properties of aerosol particles on an individual basis.

Interaction Forces Between Thermoresponsive Surface and Colloidal Particle in Aqueous Solution Studied Using Atomic Force Microscopy

2006 ◽  
Vol 942 ◽  
Author(s):  
Naoyuki Ishida ◽  
Mikio Kobayashi
Keyword(s):  
Aqueous Solution ◽  
Colloidal Particles ◽  
Interaction Force ◽  
Surface Hydrophobicity ◽  
Solution Temperature ◽  
Interaction Forces ◽  
Force Microscopy ◽  
Atomic Force ◽  
Hydrophobic Particles ◽  
Repulsive Forces

ABSTRACTThe interaction forces between poly(N-isopropylacrylamide) (PNIPAAm)-grafted surfaces and colloidal particles in an aqueous solution were investigated using an atomic force microscope (AFM). Measurements were conducted between a smooth silicon wafer on which PNIPAAm was terminally grafted and silica particles hydrophobized with a silanating reagent in an aqueous electrolyte solution under controlled temperature. Below the lower critical solution temperature (LCST) of PNIPAAm, there were large repulsive forces between the surfaces, while attractive forces were observed above LCST. When surface hydrophobicity of the particles increased, the magnitude of attractive force tended to increase. The changes of hydration state of the grafted PNIPAAm chains depending on temperature is considered to greatly alter the interaction force properties. The role of the intermolecular interaction between the PNIPAAm chains and the hydrophobic particles in the interaction forces is discussed.

scholarly journals Influence of Surface Properties on Adhesion Forces and Attachment ofStreptococcus mutansto ZirconiaIn Vitro

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Pei Yu ◽  
Chuanyong Wang ◽  
Jinglin Zhou ◽  
Li Jiang ◽  
Jing Xue ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Surface Properties ◽  
Biofilm Formation ◽  
Adhesion Force ◽  
Contact Angles ◽  
Adhesion Forces ◽  
Force Microscopy ◽  
Early Attachment ◽  
Atomic Force ◽  
Initial Adhesion

Zirconia is becoming a prevalent material in dentistry. However, any foreign bodies inserted may provide new niches for the bacteria in oral cavity. The object of this study was to explore the effect of surface properties including surface roughness and hydrophobicity on the adhesion and biofilm formation ofStreptococcus mutans(S. mutans) to zirconia. Atomic force microscopy was employed to determine the zirconia surface morphology and the adhesion forces between theS. mutansand zirconia. The results showed that the surface roughness was nanoscale and significantly different among tested groups (P<0.05): Coarse (23.94±2.52 nm) > Medium (17.00±3.81 nm) > Fine (11.89±1.68 nm). The contact angles of the Coarse group were the highest, followed by the Medium and the Fine groups. Increasing the surface roughness and hydrophobicity resulted in an increase of adhesion forces and early attachment (2 h and 4 h) ofS. mutanson the zirconia but no influence on the further development of biofilm (6 h~24 h). Our findings suggest that the surface roughness in nanoscale and hydrophobicity of zirconia had influence on theS. mutansinitial adhesion force and early attachment instead of whole stages of biofilm formation.

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